64-bit basics for Windows administrators

64-BIT FUNDAMENTALS

 The first 64-bit processor actually came out back in 1992 when Digital Equipment Corp. introduced its Alpha AXP architecture. DEC is no longer around but today 64-bit processors are offered by Intel, AMD, IBM, Hewlett-Packard and Sun Microsystems. Already, 64-bit architectures,
A 64-bit processor can process twice as many bits of data as a 32-bit chip can in the same number of compute cycles. But because it's the number of combinations of bits that really matters, this translates to much more than twice the processing power.
Moving from a 32-bit to a 64-bit architecture is a major change. Most operating systems must be modified to take advantage of the new architecture, while other software must be ported to use the 64-bit capabilities. For instance, older software is usually supported through a hardware compatibility mode (whereby the 64-bit processors support a 32-bit instruction set), through software emulation, or through the implementation of a 32-bit processor core within the 64-bit processor die (as with Intel's Itanium processors, which include an x86 processor core to run 32-bit x86 applications).
Windows Server 2003 is the first Microsoft operating system to fully support 64-bit computing (on Itanium). Learn more about processors.

• 64-bit Windows -- when and why to use it
  The decision of whether to run 64-bit Windows in an enterprise becomes much easier to make when you cast a critical eye on the application that will be the star of the show.
  
• 64-bit Watch
  We've assembled this reference guide to show you which 64-bit processors are available now for the hardware in your Windows network.
  
• The lowdown on 64-bit
  We look at the architectures of Intel's and AMD's 64-bit processors, and analyze the pros and cons of each in the Windows world.
  
• How 64-bit version of Windows differs architecturally from 32-bit version
  The x64 versions of Windows represent one of the few cases in which it is truly important for an admin to understand the underlying system architecture.
  
• A primer on PCI devices
  Most of us are familiar with standard 32-bit PCI hardware: The interface connector on the card consists of one large and one small tab, with the smaller tab to the rear. There are also 64-bit PCI cards, which have a third tab at the rear that is larger than the second one but smaller than the first.
  
• Survey says: 64-bit on readers' minds
  This survey asks users about their plans for implementing 64-bit technologies.
  
• The 64-bit push is on for Windows shops
  Microsoft's decision to make future versions of Exchange and Windows 64-bit only means IT managers may need to reassess some of their long-range hardware rollout plans.
  

64-BIT ADMINISTRATION

The IT industry is starting to migrate toward a 64-bit world, but the journey can be complicated. Read our collection of tips and advice below to help you navigate through the process.

• Use boot manager to dual-boot between 32- and 64-bit XP
  Dual-booting between the 32- and 64-bit versions of Windows XP can be difficult because they use different boot tools. Best to try a third-party boot manager.
  
• Printer drivers few for 64-bit Windows XP. Here's a workaround
  Lack of printer drivers for 64-bit Windows XP creates rasterization problems. Workarounds are scarce. Here's one.
  
• How virtualization can simplify your transition to 64-bit computing
  The IT industry is starting to migrate toward 64-bit computing, but it could be years before all mission-critical software is compatible with the new infrastructure.
  
• Buying a PC to run Vista? Consider CPU, memory issues
  Buying workstations entails tough decisions when the industry is in transition, as it is now, with the shift from 32- to 64-bit systems, as well as the upcoming release of Vista. Here's one.
  
• Purchasing workstation hardware during transitional times
  If you're buying workstation hardware, thinking back to the last transitional period in terms of operating systems and processors can help guide your purchasing decision.
  
• Tape backups may have trouble keeping up with 64-bit systems
  New 64-bit systems, like the ones based on Itanium processors, are built for speed. So is the version of Windows Server 2003 for Itanium systems. However, when you install Service Pack 1 on Windows Server 2003 for Itanium, your tape backups may slow dramatically.
  
• Microsoft releases Windows Server 2003 Scalable Networking Pack
  One of the most significant out-of-band releases for Windows Server 2003 (and 64-bit Windows XP) is an add-on called the Microsoft Windows Server 2003 Scalable Networking Pack.